Drive device for a surfboard

ABSTRACT

The invention relates to a drive device for a surfboard, comprising movable elements for increasing the propulsion resulting from said drive device. Said elements are set in motion by the user of the surfboard. The user can thus travel through the water with their surfboard while simultaneously training their body.

Surfboards have long been known as state of the art. A well-known surfboard usually consists of thermoplastic material or composite, (glass and carbon) or is made in timber construction, for example bamboo wood or balsa wood. At the bottom of the surfboards there are fixed and immovable stabilizers, called fins, which can be variable depending on the board type.

The invention in the specification (U.S. Pat. No. 8,043,134) describes a device for propelling a surfboard. The user of the surfboard stands on the surfboard and moves two fins attached to the rear of the board by moving a lever up and down. The fins move against the board to stabilize the board. The problem is that the user is always in the same position on the surfboard and there is hardly any controllability.

On a known surfboard (U.S. Pat. No. 4,464,126), the user can change his position on the board while operating the device for forward movement. A disadvantage of this kind of drive is, however, that controllability of the board is hardly given.

A goal of the invention is therefore to provide a propulsion device which achieves an improvement in the controllability of the surfboard.

According to the invention, this object is achieved by a device of the type mentioned in the introduction in that at least one movable drive fin, which can be deflected laterally, is arranged on the underside of the surfboard.

In a preferred embodiment of the invention, at least one flexible fin is arranged at the bottom of the surfboard.

The invention and further advantages are explained in more detail below with reference to some non-limiting embodiments, which are illustrated in the drawings.

FIG. 1 is a schematic representation of a cross-section through the present invention;

FIG. 2 is a schematic representation of a cross-section through the present invention in different positions of movement;

FIG. 3 is a schematic representation of the movement linkage of the present invention;

FIG. 4 is a schematic representation of a cutaway top view of the present invention;

FIG. 5 is a schematic representation of a fin;

FIG. 6 is a schematic representation of an alternative fin with variable resistance;

FIG. 7 is a schematic representation of a fin set for shallow waters;

FIG. 8 is a schematic representation of an alternative fin with an upper plateau;

FIG. 9 is a schematic representation of an alternative fin with upper and lower plateau;

FIG. 10 is a schematic representation of an alternative fin set with an upper plateau ;

FIG. 11 is a schematic representation of a cross-section through an alternative of the present invention;

FIG. 12 is a schematic representation of a cutaway top view of an alternative of the present invention.

FIG. 1 is a schematic representation of a propulsion device (1). According to FIG. 1, the propulsion device comprises a rotatable drive rod (1) which is arranged via a ball bearing (2) which is fixed in or on the upper side of the surfboard by means of a mounting plate (3). The drive rod (1) is connected via a ball joint (4) to at least one adjustable connecting rod (5). The drive rod (1) can be folded in and can be adjusted in height for different users. The drive rod (1) can be removed for transport. The connecting rod (5) is connected to a further adjustable connecting rod (5′) via a ball joint (4′). A ball joint (4″) which connects the connecting rod (5′) to at least one adjustable lever arm (6) can be provided at at least one end of the connecting rod (5′). The lever arm (6) is fixed by a rod (7) which is mounted on the upper side and underside of the surfboard by a respective ball or slide bearing (8). The pivot rod (9) is fixed on the side of the lever arm (6) opposite the connecting rod (5′). The pivot rod (9) ends in the fin (10). In order to stabilize the surfboard when the drive device is in use, a flexible fin (11) is mounted in the direction of the bow on the surfboard. The flexible fin (11) is rigidly connected to the surfboard via a rod (12). It is particularly advantageous to provide multiple moveable fins (10, 10′) one behind the other at the base of the board. This stabilizes the board and the propulsion is increased. Likewise, the training effect for the user increases.

When the drive rod (1) moves forward (re.) (See FIG. 2), the ball joints (4, 4′, 4″) and the lever arms (6 ‘) correspond with a deflection (right) of the pivot rods (9, 9’) and the associated movement of the fins (10, 10′). This pushes the surfboard forward in the water. The flexible fin (11) experiences a small deflection by the forward movement, which counteracts the respective lateral movement so that the surfboard stabilizes itself and produces a small forward movement. The drive rod (1) can be adjustable in order to allow the user to have different positions on the surfboard. Furthermore, the ball or slide bearing (2) can also be adjustably mounted on the mounting plate (3) as appropriate. The ball or slide bearing (2) stabilizes the drive rod (1) laterally and allows only a forward and backward movement. This is symbolized by the small arrow for the forward and backward movement (left) in FIG. 2. If the user makes short movements before the zero point of the drive rod (1) as shown (right), the board moves to the right. If he makes these short movements at the back (left), the board moves to the left. The respective direction depends on the arrangement of the connecting rods (5, 5′) relative to the lever arm (6.6′). By moving the drive rod (1) back and forth to the zero point, the board experiences a forward movement.

In FIG. 3, the entire linkage is shown schematically from a top view. As soon as the connecting rod (5) moves forward (in the direction of the arrow), a corresponding deflection of the pivot rods (9, 9′) and the fins (10, 10′) takes place. By deflecting the drive rod (1) as far as the mounting plate (3) towards the front or rear, the lever arm (6) tilts 180°, whereby the board can be driven in the opposite direction. If one were to look at a circuit with a car, this tilting would put it into reverse gear.

An alternative embodiment of the present invention is shown in FIG. 4. This alternative shows a rod arrangement with 4 fins (10′, 10″). As is apparent from FIG. 4, the object invention also includes other arrangements of the linkages. The desired effect can be achieved with suitable rods and levers. Alternatively, a hydraulic or cable-like arrangement would also be conceivable. An alternative form has two fins (10′, 10″), one each in front of and behind the drive rod (1). This arrangement allows the user to control the board even better.

The user of the surfboard can set the board in motion by moving the drive rod (1) and controlling it as described. In addition, the drive bar contributes to the safety of the user since he can brace himself to avoid falling off the surfboard.

In principle, the fin (10) can be rigidly attached to the pivot rod (9). However, an arrangement as shown in FIG. 5, in which the fin (10) is flexibly mounted on the pivot rod (9), is particularly advantageous. This flexibility can be achieved by a spring or such. As a result, the fin (10) adapts better to the water and the forward movement is additionally supported by the spring force.

A further alternative flexible fin (10) with variable resistance is shown in FIG. 6 When the spring (13) is under tension, the fin (10) becomes stiffer. The stiffness is changed so that the fin can be used more efficiently at higher speeds. It is particularly advantageous if the resistance can be adjusted from the drive rod (1). Suitable cable pull arrangements are conceivable.

To further increase the training effect and the propulsion, fin sets as in FIG. 7 are also conceivable. This particular type is also particularly suitable for shallow waters.

The alternative fin (10) in FIG. 8 has an upper plateau (14). This plateau (14) prevents damage to the underside of the surfboard.

In FIG. 9, the fin (10) according to the invention has an upper (14) and lower plateau (14′). The lower plateau (14′) prevents the surfboard from sinking into the subsoil of the body of water.

The alternative fin sets (10) in FIG. 10 are also provided with an upper plateau (14).

An alternative of the contrary invention is shown in Figs. The pivot rods (9, 9′) are extended by the lever arm (6, 6′). In this way, one lever arm (6, 6′) moves two fins (10) or fin sets. This arrangement stabilizes the surfboard during movement. In addition, an increase in the number of fins (10) also allows a reduction of the fins to achieve the same pre-stroke. The surfboard can have a smaller cross-section and can be moved in shallower waters. 

1. A propulsion device for a surfboard with at least two movable fins (10, 10′) which can be deflected laterally and are arranged at the underfoot of the surfboard characterized in that the fins (10, 10′) are connected by at least one connecting rod (5, 5′).
 2. The device (1) according to claim 1, characterized in that at least one flexible fin is arranged at the underfoot of the surfboard.
 3. The device (1) according to claim 1, characterized in that at least one movable fin (10) is arranged behind the pivot point (2) of the drive rod (1) and at least one movable fin (10″) is arranged in front of the pivot point (2) of the drive rod (1).
 4. The device (1) according to claim 1, characterized in that the drive rod (1) is stabilized laterally by means of a ball or slide bearing (2).
 5. The device (1) according to claim 4, characterized in that a tilting of the lever arm (6) of 180° takes place by deflecting the drive rod (1) up to the mounting plate (3) towards the front or rear.
 6. The device (1) according to claim 4, characterized in that the drive rod (1) is foldable or can be adjusted in height or removed.
 7. The device (1) according to claim 1, characterized in that at least one movable fin (10), which is laterally deflectable, is attached on the underside of the surfboard and has a plateau (14). 